1. Field of the Invention
The present invention relates to surgical cutting instruments and, more particularly, to surgical suction cutting instruments for use in cutting and removing bodily tissue from fluid unavailable surgical sites where irrigation or introduction of fluids is undesirable or proscribed, such as, for example, for use in cutting and removing tissue in the nasal cavity and paranasal sinuses or for use in cutting and removing fibroid tissue or tumors.
2. Discussion of the Prior Art
In many surgical procedures, it is desirable to provide an irrigating fluid to the surgical site to clear bodily fluids, such as blood, and to assist in the removal of cut bodily tissue. In some procedures, such as arthroscopic surgery, it is common for bodily tissue to be cut and removed using surgical suction cutting instruments, such as the Intra-Arc system by Linvatec of Largo, Florida and similar instruments by Smith & Nephew Dyonics of Andover, Mass., and for the irrigating fluid to be provided to the surgical site by separate irrigating instruments developed solely for the purpose of providing irrigation. In other procedures, the irrigating fluid is dispensed from instruments that perform other functions, such as vacuum curettes, as exemplified by U.S. Pat. Nos. 3,542,031 to Taylor, and 5,084,013 and 5,248,297 to Takase, powered cutting instruments with suction, as exemplified by U.S. Pat. Nos. 3,732,858 to Banko, 4,909,249 to Akkas et al and 5,354,265 to Mackool, and cutting instruments without suction, as exemplified by U.S. Pat. Nos. 4,642,090 to Utrata, 4,913,698 to Ito et al, 5,358,473 to Mitchell and 5,405,348 to Anspach et al. In the case of surgical suction cutting instruments for use in the eye, such as that described by Banko, the introduction of irrigating fluid also assists in replenishing the material removed from the eye in order to maintain the internal pressure of the eye and to prevent collapse of the retina and related portions.
In procedures involving cutting and removal of bodily tissue from fluid unavailable surgical sites, such as the nasal cavity and paranasal sinuses, irrigation of the surgical site is generally undesirable or prohibited in that some of the irrigating fluid can drain from the surgical site into other areas of the body, such as the lungs, resulting in unwanted complications. For this reason, endoscopic sinus surgery to cut and remove bodily tissue, such as polyps, from the nasal cavity and paranasal sinuses has typically been performed without irrigation using various manually operated and powered (i.e., motorized) cutting instruments.
When used in sinus surgery, manually operated cutting instruments have the disadvantage of tending to rip or tear bodily tissue as the tissue is cut causing unwanted trauma to surrounding mucosal tissue and excessive bleeding. Furthermore, manually operated cutting instruments must typically be withdrawn from the cavity or sinus to remove cut bodily tissue necessitating frequent substitution of instruments and increasing operating time.
Powered cutting instruments for use in sinus surgery, such as the surgical suction cutting instruments known as the Hummer micro-debrider by Stryker Endoscopy of San Jose, Calif. and the BlackStar Wizard micro-debrider by Xomed Surgical Products of Jacksonville, Fla., can reduce operating time by aspirating cut bodily tissue through the lumen of an inner tubular member rotatably received within an outer tubular member. The distal end of the inner tubular member has a surface or edge for engaging tissue via an opening in the distal end of the outer tubular member; and, as the inner tubular member is rotatably driven at its proximal end, for example by a motorized handpiece, the surface or edge of the inner tubular member will cooperate with the opening in the outer tubular member to shear, cut or shave tissue. In use, such powered cutting instruments are usually positioned in the nasal passage with other instruments such as a sinus endoscope; and, as a result, the inner and outer tubular members must be made small enough to maneuver within the limited space of the nasal passage without contacting the other instruments or obstructing the surgeon's view of the surgical site. The small size of the instruments increases the likelihood of cut bodily tissue clogging the lumen of the inner tubular member.
Where the powered suction cutting instrument has no irrigating feature, clogging of cut bodily tissue in the lumen of the inner tubular member frequently occurs requiring that the instrument be removed from the surgical site and dipped in a flushing fluid, such as saline, to clear the lumen of clogged tissue, thereby increasing operating time and the likelihood of blood accumulating at the surgical site. Where the powered cutting instrument has a cannula disposed concentrically around the outer tubular member for self-irrigation, a relatively large portion of the irrigating fluid dispensed by the cannula is deposited at the surgical site. As mentioned previously, in anatomical spaces such as the nasal cavity and paranasal sinuses, irrigation of the surgical site is undesirable or prohibited in that the irrigating fluid can drain from the surgical site into the lungs of the patient causing the patient to drown. Furthermore, it is undesirable to irrigate other fluid unavailable surgical sites during cutting and removal of tissue dependent upon the type and location of the tissue. For example, when removing fibroid tumors during minimally invasive (e.g., laparascopic) procedures, it is desirable to provide irrigation to assist suction removal of cut tissue; however, it is undesirable to irrigate the surgical site in that the irrigating fluid will tend to pool.